Chemical modification of cellulose and products thereof



United States Patent 3,388,118 CHEMICAL MGDEI ICATICN 0F CELLULOSE ANDPRODUCTS THEREGF Giuliana C. Tesoro, Dobbs Ferry, N.Y., assignor to J.P. Stevens 8: Co., Inc, New York, N.Y., a corporation of Delaware NoDrawing. Filed Apr. 23, 1965, Ser. No. 456,526 17 Claims. (Cl. 260212)ABSTRACT OF THE DISCLQSURE A method of modifying cellulose withselective modifying reagents in the class of trialkyl phosphites,ammonia, hydrazine, diamines, halides, hydrophobic polyamines,bismercaptans, alkali metal sulfides, disulfides and polysulfides,thiourea, tertiary amines and hydrophobic mercaptans, comprisingreacting such reagents at elevated temperatures with a cellulose polymerwhich has been previously modified so as to have the structurenocnzu-oownnnx R! where R and R are selected from the group consistingof hydrogen, lower alkyl, alkoxymethyl, an d hydroxymethyl, X isselected from the group consistmg of chlorine, bromine and iodine, and nis an integer of from 1 to 5.

The present invention relates to a method of modifying a materialcomprising cellulose polymers, and to the material so modified. Moreparticularly, the present invention relates to a method of modifyinghalogen-containing cellulose polymers to impart specific desirableproperties.

It is a desirable objective to modify cellulose to impart specificfunctional properties. A major drawback to such modification is thatcellulose is relatively inert and it is therefore difiicult tochemically modify the polymer.

There have been various proposals concerning chemical modification ofcellulose to provide a more reactive form, which, in turn, could beuseful as an intermediate for preparing the various end products.However, there has always been a problem that the preparation of theintermediate often has a deleterious effect on the properties of thecellulose itself so that the end product is necessarily inferior inquality.

In view of the foregoing, it is an object of the present invention toprovide a method for modifying halogencontaining cellulose to impartspecific properties.

It is a further object of the present invention to provide a method fortreating halogen-containing cellulose to impart fiameretardantproperties.

It is another object of the present invention to provide a method formodifying halogen-containing cellulose to impart water-repellantproperties.

It is an additional object of the present invention to provide a methodfor modifying halogen-containing cellulose to impart improvedresilience.

It is another object of the present invention to use as an intermediatea halogen-containing cellulose prepared in a manner which minimizesdestruction of the cellulose polymers.

It is another object of the present invention to provide a method ofimproving the reacting of halogen-containing cellulose by preferentialsubstitution of one halogen species for another.

Halogen-containing cellulose is preferably prepared by treating thecellulose with compounds having the following generic formula:

ROCH lTI-COWHQJC 3,388,11 Patented June 11, 1968 lCC in which R and Rare selected from the group consisting of hydrogen, lower alkyl,hydroxymethyl and alkoxymethyl; X is halogen (chlorine, bromine, iodine)and n is an integer having a value of 1 to 5; in the presence of. anacidic or acid forming catalyst. The reaction which takes place whencellulose polymers are treated with the compounds of Formula 1 can beschematically represented by Equation 2, where the symbol Cell-OH isused to represent a cellulose molecule:

Compounds of Formula 1 in which n=l are preferred, since they have moredesirable solubility and reactivity than those in which n issubstantially more than 1.

Introduction of halogen by Reaction 2 shown above, is advantageousbecause the cellulose polymer is not degraded as it would be if thionylchloride, for example, were used. However, it is to be understood thatthe reactions discussed herein for the treatment of halogencontainingcellulose are not limited to such intermediate produced by Reaction 2.Any cellulose containing reactive halogen is suitable for use inaccordance with the methods of the present invention.

The compounds of Formula 1 can be prepared by known methods, generallyby the reaction of formaldehyde with suitable halo-substitutedcarboxamides. For example, the reaction of formaldehyde withchloro-acetamide yields a product of the formula:

HOCHZNHCOCHQCI (3) Product 3 is a species of the generic compoundsrepresented by Formula 1 in which R and R are hydrogen, n=1 andX=chlorine. Other compounds representative of Formula 1 can be preparedby similar methods.

The reaction of the compounds of Formula 1 with cellulose, exemplifiedby Equation 2, is catalyzed by acidic compounds, and by compoundscapable of liberating protons on heating. Suitable catalysts areWatersoluble, non-volatile organic acids such as oxalic, citric,tartaric acid and the like; salts of mineral acids with ammonia andamines such as amine hydrochlorides, am monium nitrate and the like, andsalts of mineral acids with bivalent metals such as magnesium, zinc,calcium and the like. The choice of catalyst is not critical, and anyacid or acid-forming substance can be employed. Free mineral acids arepreferably avoided because, although they are effective in catalyzingthe desired reaction, they have a tendency to degrade the celluloseunder the conditions of reaction.

The reaction of the cellulose with the compounds of Formula 1 isconducted by contacting the cellulose with a solution containing thereagent and catalyst, drying, and subsequently heating for a briefperiod to drive the reaction to substantial completion. In the case oftextile cellulose, the treatment is conveniently carried out by paddingthe textile with the reagent-catalyst solution, driving off the solventby drying in a forced draft oven and then heating or curing to completethe reaction. Preferably, water should be used as the solvent since thissimplifies the padding operation and minimizes handling problems.

The heating or curing step can be carried out by any convenient means.The time and temperature of heating can be varied over a broad range anddepend on the particular catalyst and catalyst concentration used.Longer times should be used with lower temperatures. In general,

3 4 reaction times of about 2 to 20 minutes at about 110 C. TearStrength--ASTM-D142463 (lbs). to 175 C. are sufiicient. After theheating step, the Porportions and percentages are by weight unlesstreated cellulose can be washed to remove unrcacted re otherwise noted.agent and catalyst. Chemical analysis of the reaction EXAMPLE 1 productmay be conducted to establish (1) the halogen content, (2) the nitrogencontent, and (3) the methylene (bound formaldehyde) content Thepreferred product contains one atom of halogen for each nitrogen and foreach methylene ether group introduced.

Modified cellulose containing 0.1 to 1.0 meq./ g. milli- Samples ofplain weave cotton fabric (commonly known as 80 x 80 print cloth) wereconditioned at 65% relative humidity at a temperature of 21 C., andweighed on an analytical balance. They were then treated with aqueoussolutions of N-methylol-chloroacetamide equivalents per gram) of halogencan easily be obtained (HOCH NHCOCH Cl) by h Procedure higher halo-gm iIt be containing various types and amounts of catalysts, using obtainedby repeating the treatment untll the desired a laboratory paddel. andSetting the rolls at such a Pres halogen content is sure as to give a100% wet pickup, by weight. The fabric The Procass Outhned above can beearned out samples so treated were framed to the original dimensions1111056 m the form of film, fib r, arn, woven or kn fi f d dried at 60C., then cured in a forced draft oven, as fabric or non-wovenstructures. The treatment is appliindicated below The cured samples wererinsed than cable to the modification of natural cellulose, such asoughly in a non ionic dfitergem solution at C" then Comm, linen, Wood,and 0f regenerated Cellulose Such as in water and finally dried onframes. The dried samples Y It is Particularly useful for themodification 0f were again conditioned as above, and the weight increaseCommonly used textile 66111110568, including cotton and due to thetreatment calculated. The following results regenerated cellulosefabrics. In addition, a material were obtamed:

Percent Percent Catalyst Curing Time Percent Sample Reagent added toreag. 111 Min. at Weight Percent Applied, solution 150 0. Increase YieldOWF+ 18.6 2 6. 8 43 18. 6 5 8. 6 54 15. 2 5 6. 0 46 15. 0 15 6. 49 19. 22 7. 0 43 19.2 5 9.0 18.8 2 6. 5 4O E-2. 18. 8 1 Citric Acid. 5 9. 57

1 Catalyst XRFProduct of Onyx Chemical 00. (Jersey City, NJ.) (aminehydrochloride solution).

? Accelerator MX-Product of American Cyanamid Co. (magnesium chloridesolution) On weight of Fabric Treated.

composed in part of cellulose can also be treated in ac- The analysis ofsamples B-1 and B-2 gave the followcordance with the inventive process.ing results:

8 1 Percent 01 Percent N Percent HCHO Cl Ratio HCHO p Found Calcd. FoundCalcd. Found Calcd. Found Calcd.

fr. w.g. fr. w.g. fr. w.g.

Set forth below are examples which illustrate the man- EXAMPLE 2 ner inwhich halogen is introduced into cellulose. The test procedures referredto in the examples are identified Example 1 was repeated, but instead ofthe plam as follows: weave cotton fabric (commonly known as x 80 printFormaldehydel. r01 Sci. 5, 734 (1961). cloth) a cotton twist twill(weight 8 oz./square Idalogem-Saponification in 1 N KOH in ethyleneyard) fabric, dyed with vat dyestulfs, was used. The folglycol for twohours at reflux temperature, followed by lowmg were obtained:

Percent Catalyst Curing Percent Sample Reagent OWB, Time in WeightPercent Applied, Percent Min. at Increase Yield OWF C.

Analytical data on the treated samples were as follows:

Percent 01 PercentN Percent HCHO Cl/N Ratio Cl/HCHO Ratio 1 swmpe FoundCalcd.fr. Found Calcd. 1r. Found Calcdir. Found Calcd. Found Calcd.

w.g. w.g. w.g.

conductometric titration with standard AgNO using Ag/ EXAMPLE 3 AgClelectrodes.

Crease RecoveryASTM-D-12956OT (in degrees). Example 1 was repeated, butinstead of N-methylol Tensile StrengthRavel Strip Method ASTM-D-chloroacetamide, the corresponding methyl ether, N-

1682-59'1 (lbs). 75 methoxymethyl chloroacetamine was used in thepresence 5 6 of a mixed catalyst (2% citric acid and 2% Accelerator thestable phosphonate grouping in the cellulose molecule. MX) under thecuring conditions specified below: The reaction of Equation 3 ispreferably conducted at an Percent min Percent elevated temperatureabove about 100 C. and anexcess Sample Reactant Tempemim Weight Percentof trralkyl phosphlte is generally used. The reaction repn IncreaseYield quires prolonged heating, and can be conveniently carried OWE 2mmutes) out by immersing the halogen-modified cellulose in a solu- 3.2at tion of the phosphite,'and heating the solution by any suitablemeans. The properties of the treated samples were as follows: Example 4,below, illustrates the reaction of Equation OR (W+F) Twila Tear 3 andshows the improvement in flame-retarding prop- Sample Strerigth Strengtherties obtained by such treatment.

Dry Wet W W A-1 192 205 45 1.3 EXAMPLE 4 A-2 192 227 42 1.3 Untreated150 160 60 Chloroacetamido methyl cellulose (CAMC) samples which wereprepared by reacting N-methylol-chloroacetamide with cotton twill(weight: 8 oz./square yard) in The treated samples exhibited an increasein crease the presence of 3% XRF catalyst and cured at 150 C. forrecovery over that of the untreated control by virtue of 15 minutesaccording to the procedure described in Exthe formation of formaldehydefrom the N-methoxyample 1 were treated with various trialkyl-phosphites.methyl chloroacetamide, which formaldehyde reacted with a h of trialkyl-phosphites Was dissolved in dimethylth ll l t cause -li kiformamide to produce a solution by weight of the The modified celluloseobtained according to the presp p Respective Samples pp im W ight: 20ent invention has useful and desirable properties. The g-) W e im rsedinto 60 g. of each of the trialkyl presence of the halogen imparts abroad range of reactiv- 25 phosphite solutions. After 3 hours ofreaction at a reflux ity that will be more fully discussed andillustrated below. temp of about C, the tffiated Samples Were In spiteof this reactivity, however, the halogen-modified thoroughly rinsed indimethylfofmamide, and then rinsed cellulose is a very stable compoundunder all commonly in Water and finally dried 011 frames n a orced draftencountered conditions of storage. This property is espe- Ovenciallyimportant whenever it is desired, for example, to Analysis of CAMCsamples before treatment: treat the cellulose in the form of fiber oryarn, convert the halogen-containing modified cellulose to a manufac-Chlorine, percent 2.3 tured product such as a fabric or even a garment,and Meq./g. 0.65 then carry out a further modification, such ascross-link- Nitrogen, percent 1.02 ing. MeqJg. 0.73 The reactivity ofthe halogen in the modified cellulose Formaldehyde, percent 2.02 makesfurther modification possible for the purpose of Meq./g. 0.67 impartingspecific functional properties to the cellulose. Typical examples ofthese further modifications are dis- Analysis of CAMC samples aftertreatment with the cussed below, and illustrated by the examples.trialkylphosphites:

Resid. Cl Percent Reagent Percent N Percent P Mequ./g. content, Yield inFound Found mequ./g. reaction w.

plrospnite Trimethyl phosphite 1. 13 2.07 0.66 0. 1 ca. 100 Triethylphosplrite. 1. l3 1. 35 0. 44 0. 1 66 Tributyi phosphite. l 01 0.81 0.260.1 47 Triallyl phosphite 1. 16 1. 24 0. 4 0. 15 61 The reaction withtrialkyl phosphites to obtain cellulose amido-phosphonates havingdurable flame retardant propemes 1S represented by Equauon 3: Thesamples treated with trimethyl and triethyl phos- CQ1IOOHIIICO(CH)X1X(Rmm phite were exposed to alkaline scouring (2.0% Na CO R 0 0.5% IgeponT-73, C. 1 hour, 1:30 fabric-liquor ratio) in order to test thestability of the phosphonates.

[I 0 110011 N-CO C'I P OR R"X e I 2) )2 The analyses and the flame testafter the scouring speci- (3) 6O fied above gave the following results:

Percent N Percent P Char Length Reagent in Vert.

Found Retained Found Retained Flame Test (inches)* Trirnethylphosphite. 1. 11 98 2. 10 100 5. 0 Trietnylplzosphite 1. 11 98 1. 34 1006. 3

*Vertical Flame Resistance Test-AATCC-S i-1952.

In Equation 3, R" represents an alkyl or alkenyl radi- Thehalogen-containing cellulose, made in accordance cal. Thephosphorus-containing modified cellulose prodwith the present inventionmay be reacted with comucts obtained in the manner shown in Equation 3exhibit pounds to introduce hydrophobic groups and thereby imdurableflame-retardant properties due to the presence of 75 part waterrepellency. Thus, for example, reactions with amines or mercaptans arerepresented by Equations 4 and 5, respectively:

8 Analysis and properties of CAMC samples before treatment with amines:

'O CH X HN CeHOCHZII C z) Percent weight gain 4.6 Percent Cl, found 1.80eeuoonm-cownmnmnm l r m we f (4) Percent N, found 0.04 Calcd. from w.g.0.58 Ce11OCHZNCO(CH2)nX ESQ, Percent HCO, found 1.49 t, Calcd. from W.g1.25 Cl/HCHO ratio, found 1.21 0H Calcd. from w.g. 1.18

Cone. of Amino Percent Percent Crease Recovery (W-l-F) Diarmne ReagentSolvent Solution (g./l.) Weight 01 Retained Change Dry Wet None 238 224Di(rnethoxyethyl) amine 250 237 N ,N-dirnethyl ethylene diann 260 243Piperazine 0 12 241 236 CellOGHzIiT-COWHzhSQ (5) R Significant creaserecovery improvements due to cross- In Equations 4 and 5, R' representshydrogen or lower alkyl and Q represents a hydrophobic monovalentlinking are noted.

Halogen-containing cellulose may also be reacted with alkali sulfide,disulfide or polysulfide to obtain the corresponding cross-linkedthioether, cross-linked disulfide or cross-linked polysulfide. Example6, set forth below, is illustrative of this embodiment of the invention.

by treatment with ammonia, hydrazine, or polyamine compounds to improveresilience. In the instance where the cellulose is in fabric form,increased crease recovery results. Equations 6 and 7 typify thismodification:

R! RI EXAMPLE 6 Chloroacetamido methyl cellulose (CAMC) samples(analysis and properties specified .in Example 5) were treated withaqueous sodium sulfide and sodium disulfide solutions using a laboratorypadder and setting the rolls at such a pressure as to give 100% wetpickup. The samples so treated. were framed to original dimensions,dried and cured in a forced draft oven at 150 C. for 5 minutes, orsteamed in a laboratory steamer for 30 minutes.

After curing or steaming, the samples were rinsed in dilute acidic acidsolution and washed thoroughly in nonionic detergent solution at -70 C.Finally, the samples were dried on frames. The following results wereobtained:

Reagent Reagent OWF Percent Reaction Conditions Found Dry Wet 9 Cure:150 0., 5 Min.... 5 Steam: 30 Min 0 EXAMPLE 5 Chloroacetamidomethylcellulose (CAMC) samples, which were prepared by reacting N-methylolchloroacetamide with 80 X 80 cotton in the presence of 3% XRF Reactionsof halogen-containing cellulose with bis-mer-.

capto com ounds to obtain cross-linked cellulose having improvedresilience, is illustrated by Equation 8:

catalyst and cured at 150 C. for 5 minutes according c 110c g rvmlqcmocen ZHX to the procedure described in Example 1, and which had theanalyses and properties specified below, were treated with selectedamines. The amines were dissolved in organic solvents and thehalogenated fabric (CAMC) samples (approximate weight: 14 g. per sample)were im- 7 Among other reactions to which the halogen-containingcellulose can be subjected to obtain selected modified products are thefollowing:

(a) Reaction with thiourea to obtain the isothiuronium Percent S CreaseRecovery(WI-F) 9. halide, and further the corresponding mercaptan anddisulfide:

S H CellO CHgN-CO(CH2) RX H N( )=NH NaOH CellO CHzN-C 0 (CH SH -l-(NHzhC O NaX (b) Reaction with tertiary amines to obtain a modifiedcellulose containing quaternary ammonium groups:

R CcllOCHzlTI-CO(CH;)..X NR

R R n R CellO CH-zlTlC O (GH2)..N R X- R R The nature of the particularhalogen atom X affects the reactivity of the cellulose derivative in theexpected manner, with reactivity generally increasing in the order of IBr CL When the reaction of the chlorine containing cellulose does notproceed at a satisfactory rate, it is possible to replace the chlorinewith a more reactive halogen even after the halogenated cellulosederivative has been prepared and isolated, by treating the chloroalkylamidomethyl cellulose with alkali iodide, as shown in Example 7below:

EXAMPLE 7 Chloroacetamido methyl cellulose sample obtained by reactingcotton samples with N-methylol-chloroacetamide according to theprocedure described in Example 1 (Sample A: 80x 80 print cloth, Clcontent 1.75%, 0.49 meq./ -g., fabric and Sample B: twist twill, Clcontent 2.31%, 0.65 meq./g., fabric) were treated with an excess of KIdissolved in acetone. The samples (approximate weight g.) were immersedinto 1400 ml. of 10 g./l. KI solution. After a reaction time of 8 hoursat reflux temperature, the samples were thoroughly rinsed in acetone,then in water and dried on frames in a forced draft oven.

dissolve appreciable amounts of the required acidic catalyst (e.g.,hydrocarbon solvents) are not suitable alone but can be used in mixtureswith other solvents, if desired.

The concentration of reagent in the solution used to impregnate thecellulose depends on the extent of reaction required. Generally,solutions containing 3 to of the reagent selected can be appliedconveniently. As suggested above, repeated treatments can be used if ahigher degree of modification of the cellulose is needed. Theconcentration of acidic catalyst can vary within Wide limits dependingon the acidity and effectiveness of the catalyst and on theconcentration of reagent. Amounts of 1% to 8% based on the weight ofsolution are preferred.

It is to be appreciated that the examples set forth above are intendedto be merely illustrative and variations therein may be made by oneskilled in the art without departing from the spirit and scope of thisinvention.

What is claimed is:

1. A process comprising the steps of providing cellulose polymers whichhave been modified by reaction with a compound having the formula:

in which R is selected from the group of alkyl radicals and alkenylradicals of from 1 to 4 carbon atoms, for a time sufiicient to causeaddition of phos phorous to said modified cellulose polymer. 2. Theprocess of claim 1 in which the trialkyl phosphite is trimethylphosphite.

3. The process of claim 1 in which the trialkyl phosphite is triethylphosphite.

4. A process comprising the steps of providing cellu- Percent IodineTotal Percent Con- It is evident from the above discussion that thehalogen-containing cellulose of the present invention is a usefulintermediate for many diverse reactions in which unmodified cellulosewould be essentially inert. The reactions illustrated by Equations 4through 8 are preferably conducted by impregnating thehalogen-containing cellulose with a solution of the desired reagent,drying the cellulose to eliminate the solvent and heating to drive thereaction to completion. In general, reaction temperatures of the orderof 125 C., to 175 C. are suflicient, the time at which the cellulose ismaintained at such temperature being selected to provide the desiredextent of reaction.

Examples 1 through 3, set forth above, involve the use of water as thesolvent for the halogen-containing reaction compound utilized inaccordance with this invention to introduce halogen into cellulosepolymers. As indicated, water is preferred because it is inexpensive anddoes not introduce any handling complications. However, other organicsolvents can also be used for the preparation of the halogen containingcellulose either alone or in mixtures with water. It is preferable touse polar solvents such as methanol, ethanol, dimethylformamide,dioxane, tetrahydrofuran, acetone and the like. Solvents which do notswell the cellulose and do not lose polymers which have been modified byreaction with a compound having the formula:

in which R and R are selected from the group consisting of hydrogen,lower alkyl, hydroxymethyl and alkoxyrnethyl, X is selected from thegroup consisting of chlorine, bromine and iodine, and n is an integer inthe range of from 1 to 5, to introduce reactive halogen, and reactingthe modified cellulose polymers with a reagent selected from a groupconsisting of ammonia, hydrazine, bis-primary amine and bis-secondaryamine, at a temperature between about 125 C. and 175 C. and for a periodof time sufficient to cause cross-linking of said modified cellulosepolymer through said reagent. 7

5. The process of claim 4 in which the bis-secondary amine isN,N'-dimethyl ethylene diamine.

6. The process of claim 4 in which the bis-secondary amine is,piperazine.

7. A process comprising the steps of providing cellu- 11 lose polymerswhich have been modified by reaction with a compound having the formula:

RoomN-CowHnnX in which R and R are selected from the group consisting ofhydrogen, lower alkyl, hydroxymethyl and alkoxymethyl, X is selectedfrom the group consisting of chlorine, bromine and iodine, and n is aninteger in the range of from 1 to S, to introduce reactive halogen, andtreating the modified cellulose with a solution of an alkali salt of asecond halide which is more reactive than said reactive halogen, at orabove the refluxing temperature of said solution of alkali salt of asecond halide, for a time sufficient to substitute said second halidefor at least a portion of the said reaction halogen contained in saidmodified cellulose.

8. A process comprising the steps of providing cellulose polymers whichhave been modified by reaction with a compound having the formula:

ROCHgN-CO(CH2)nX in which R and R are selected from the group consistingof hydrogen, lower alkyl, hydroxymethyl and alkoxymethyl, X is selectedfrom the group consisting of chlorine, bromine and iodine, and n is aninteger in the range of from 1 to 5, to introduce reactive halogen, andreacting the modified cellulose polymers with an amine of the formula:

in which R is selected from the group of hydrogen and lower alkyl and Qis a hydrophobic monovalent radical, selected from the group consistingof aliphatic, fluorinated aliphatic and silicon-containing aliphaticradicals at a temperature of between about 125 C. and 175 C. for aperiod of time sufficient to cause addition of said hydrophobic radicalto said modified cellulose polymer.

9. A process comprising the steps of providing cellulose polymers whichhave been modified by reaction with a compound having the formula:

ROCH2IITCO (C H2) "X in which R and R are selected from the groupconsisting of hydrogen, lower alkyl, hydroxymethyl, and

alkoxymethyl, X is selected from the group consisting of chlorine,bromine and iodine, and n is an integer in the range of from 1 to 5, tointroduce reactive halogen, and reacting the modified cellulose polymerswith a compound of the formula:

in which R is a divalent organic radical, at a temperature of betweenabout 125 C. and 175 C. for a time sufficient to cause cross-linking ofsaid modified cellulose polymers through said reagent. 10. A processcomprising the steps of providing cellulose polymers which have beenmodified by reaction with a compound having the formula:

in which R and R are selected from the group consisting of hydrogen,lower alkyl, hydroxymethyl and alkoxymethyl, X is selected from thegroup consisting of chlorine, bromine and iodine, and n is an integer inthe range of from 1 to 5, to introduce reactive halogen, and reactingthe modified cellulose polymers with an alkali metal sulfide, at atemperature above about 100 C. for a time sufiicient to cause additionof sulfur to said modified cellulose polymers.

11. The process of claim 10 in which the alkali sulfide is sodiumsulfide.

12. A process comprising the steps of providing cellulose polymers whichhave been modified by reaction with a compound having the formula:

ROCH2N-CO(CHz)nX in which R and R are selected from the group consistingof hydrogen, lower alkyl, hydroxymethyl and alkoxyrnethyl, X is selectedfrom the group consisting of chlorine, bromine and iodine, and n is aninteger in the range of from 1 to 5, to introduce reactive halogen, andreacting the modified cellulose polymers with an alkali disulfide, at atempera ture above about C. for a time sufficient to cause addition ofsulfur to said modified cellulose polymers.

13. The process of claim 12 in which the alkali disulfide is sodiumdisulfide.

14. A process comprising the steps of providing cellulose polymers whichhave been modified by reaction withv a compound having the formula:

ROCH2NCO(CH2)nX in which R and R are selected from the group consistingof hydrogen, lower alkyl, hydroxymethyl and alkoxymethyl, X is selectedfrom the group consisting of chlorine, bromine and iodine, and n is aninteger in the range of from 1 to 5, to introduce reactive halogen, andreacting the modified cellulose polymers with an alkali metalpolysulfide, at a temperature above about 100 C. for a time suflicientto cause addition of sulfur to said modified cellulose polymere.

15. A process comprising the steps of providing cellulose polymers whichhave been modified by reaction with. a compound having the formula:

in which R and R are selected from the group consisting of hydrogen,lower alkyl, hydroxymethyl and alkoxymethyl, X is selected from thegroup consisting of chlorine, bromine and iodine, and n is an integer inthe range of from 1 to 5, to introduce reactive halogen, and reactingthe modified cellulose polymers with thiourea, at a temperature ofbetween about C. and C. for a time sufiicient to cause addition ofsulfur to said modified cellulose polymers.

16. A process comprising the steps of providing cellulose polymers whichhave been modified by reaction with a compound having the formula:

in which R and R are selected from the group consisting of hydrogenlower alkyl, hydroxymethyl and alkoxyrnethyl, X is selected from thegroup consisting of chlorine, bromine and iodine, and n is an integer inthe range of from 1 to 5, to introduce reactive halogen, and reactingthe modified cellulose polymers with a tertiary amine.

-17. A process comprising the steps of providing cellulose polymerswhich have been modified by reaction with a compound having the formula:

in which R and R are selected from the group consisting of hydrogen,lower alkyl, hydroxymethyl and alkoxymethyl, X is selected from thegroup consist- 13 ing of chlorine, bromine and iodine, and n is aninteger in the range of from 1 to 5, to introduce reactive halogen, andreacting the modified cellulose polymers with a mercaptan of theformula:

in which Q represents a hydrophobic monovalent radical, at a temperatureof between about 125 C. to

175 C. for a time sufficient to cause addition of said hydrophobicradical to said modified cellulose polymers.

No references cited.

DONALD E. CZAJA, Primary Examiner.

R. W. MULCAHY, Assistant Examiner.

